Smokers with a history of panic attacks represent a common, albeit understudied, segment of the smoking population who may be at heightened risk for continued nicotine dependence and its associated morbidity and mortality. Though researchers have attempted to understand the impact of certain emotional disorders on the relative degree of success in smoking cessation, research has not examined the impact of panic-related problems on smoking cessation outcomes. To address this gap in the existing literature, the present R21 proposal seeks to test the extent to which a history of panic attacks interferes with successful smoking cessation. The project also will clarify theoretically relevant negative emotional processes involved with smoking cessation more generally. Findings from the proposed investigation should result in improved methods of identifying smokers at-risk for relapse, so that they may be targeted for nicotine dependence treatments that will meet their specific needs. The proposed study employs a prospective design to follow for three months a sample of 84 smokers with and without a history of panic attacks after they attempt to quit smoking on their own. Subjects will complete a diagnostic interview and a medical screening, provide saliva for cotinine analysis, and will complete a set of self-report measures assessing theoretically relevant emotional and smoking characteristics. They also will complete a well-established voluntary hyperventilation challenge procedure on a day prior to their cessation attempt on which they will come to the laboratory not smoking for a 12-hour experimental abstinence period. Beginning on quit day and also at days 3, 7, 14, 28, and 90, subjects will return to the study center for assessment of smoking outcomes, psychological/emotional status, and withdrawal symptoms. Because smokers with panic attacks may represent a recalcitrant group of smokers who are at-risk for continued nicotine dependence, these research findings should hold considerable clinical and public health significance and may result in the development of specialized treatment approaches for this population. [unreadable] [unreadable]